U.S. patent application number 12/178799 was filed with the patent office on 2009-01-29 for composite lens.
This patent application is currently assigned to Sanyo Electric Co., Ltd. Invention is credited to Yuma Aoi, Youhei Nakagawa.
Application Number | 20090029117 12/178799 |
Document ID | / |
Family ID | 40295655 |
Filed Date | 2009-01-29 |
United States Patent
Application |
20090029117 |
Kind Code |
A1 |
Aoi; Yuma ; et al. |
January 29, 2009 |
COMPOSITE LENS
Abstract
A composite lens that prevents insufficient hardening of an
ultraviolet curable resin near the periphery of an optically
effective portion. The composite lens includes a plastic lens and a
resin layer. The plastic lens includes the optically effective
portion and a flange surrounding the optically effective portion.
The resin layer is formed from an ultraviolet curable resin and
arranged in contact with the optically effective portion. The
flange includes a diffusion portion which diffuses ultraviolet
light irradiating the plastic lens toward the resin layer through
the plastic lens.
Inventors: |
Aoi; Yuma; (Hirakata-shi,
JP) ; Nakagawa; Youhei; (Neyagawa-shi, JP) |
Correspondence
Address: |
OCCHIUTI ROHLICEK & TSAO, LLP
10 FAWCETT STREET
CAMBRIDGE
MA
02138
US
|
Assignee: |
Sanyo Electric Co., Ltd
Moriguchi-shi
JP
|
Family ID: |
40295655 |
Appl. No.: |
12/178799 |
Filed: |
July 24, 2008 |
Current U.S.
Class: |
428/192 |
Current CPC
Class: |
G02B 5/1866 20130101;
G02B 3/00 20130101; Y10T 428/24777 20150115 |
Class at
Publication: |
428/192 |
International
Class: |
B32B 23/00 20060101
B32B023/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 26, 2007 |
JP |
2007-194388 |
Claims
1. A composite lens comprising: a plastic lens including an
optically effective portion and a flange surrounding the optically
effective portion; and a resin layer formed from an ultraviolet
curable resin and arranged in contact with the optically effective
portion; wherein the flange includes a diffusion portion which
diffuses ultraviolet light irradiating the plastic lens toward the
resin layer through the plastic lens.
2. The composite lens according to claim 1, wherein the diffusion
portion is a groove surrounding the optically effective
portion.
3. The composite lens according to claim 1, wherein the diffusion
portion is an embossed surface surrounding the optically effective
portion.
4. The composite lens according to claim 1, wherein the diffusion
portion is a projection surrounding the optically effective
portion.
5. The composite lens according to claim 1, wherein the diffusion
portion is a diffraction grating surrounding the optically
effective portion.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is based upon and claims the benefit of
priority from the prior Japanese Patent Application No.
2007-194388, filed on Jul. 26, 2007, the entire contents of which
are incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to a composite lens, and more
particularly, to a composite lens suitable for use in a compact
image capturing device.
[0003] A composite lens, which corrects aberration with a single
lens, is formed from material having different refractive indexes.
A composite lens that is formed by depositing light transmissible
resin on an optically effective surface of a lens is widely used.
Japanese Laid-Open Patent Publication Nos. 62-227711 and 5-34509
describe methods for manufacturing a composite lens by using a
glass lens as the base material of the composite lens and an
ultraviolet curable resin as the deposited resin.
[0004] The formation of the prior art composite lens will now be
discussed. An injection molded plastic lens is used as the lens
that serves as the base material. An ultraviolet curable resin is
used to form a resin layer. The resin layer is formed by molding
ultraviolet curable resin and hardening the molded resin with
ultraviolet rays.
[0005] The plastic lens is formed through injection molding. Thus,
an annular flange having a uniform thickness is formed outwards
from an optically effective portion. Ultraviolet curable resin is
then charged into a gap between the plastic lens and a mold. The
resin is then pressurized to form the resin layer. Subsequently, as
shown in FIG. 1(a), the side of the lens 1 that is distant from the
mold 3, that is, the side opposite the resin layer, is irradiated
with ultraviolet light 41. The plastic lens 1 is uniformly
irradiated with the ultraviolet light 41. The ultraviolet light 41
is refracted by the plastic lens 1 before reaching the ultraviolet
curable resin 2. When a convex lens is formed by the optically
effective portion of the plastic lens 1 (in FIG. 1(b), the portion
corresponding to x=-0.9 to +0.9), the optically effective portion
refracts the ultraviolet light 41, which is formed by parallel
light rays. This converges the ultraviolet light 41 in the
direction of the optical axis. The ultraviolet light 41 irradiating
the flange of the plastic lens 1 is not refracted and thus
continues to travel straight. As a result, the intensity of the
ultraviolet light 41 after passing through the plastic lens 1
becomes maximum near the optical axis and gradually decreases
toward the periphery of the optically effective portion. The
intensity is minimum at the part of the optically effective portion
in the plastic lens 1 that is near the flange (in FIG. 1(b), the
positions corresponding to x=.+-.0.8). The intensity increases
again from the flange (in FIG. 1(b), the portions corresponding to
x<-0.9 and x>+0.9) and then becomes constant. The ultraviolet
light irradiating parts of the optically effective portion that is
located near the flange of the plastic lens is refracted in the
direction of the optical axis. However, the ultraviolet light
irradiating the flange is not directed toward the optical axis.
[0006] As a result, in the optically effective portion of the
plastic lens, the ultraviolet light that reaches the ultraviolet
curable resin near the flange is insufficient. This is problematic
in that the hardening of the ultraviolet curable resin at this part
becomes insufficient.
SUMMARY OF THE INVENTION
[0007] The present invention provides a composite lens that
prevents insufficient hardening of the ultraviolet curable resin
near the periphery of the optically effective portion by
irradiating the part of the optically effective portion in the
plastic lens located near the flange with sufficient ultraviolet
light.
[0008] One aspect of the present invention is a composite lens
including a plastic lens and a resin layer. The plastic lens
includes an optically effective portion and a flange surrounding
the optically effective portion. The resin layer is formed from an
ultraviolet curable resin and arranged in contact with the
optically effective portion. The flange includes a diffusion
portion which diffuses ultraviolet light irradiating the plastic
lens toward the resin layer through the plastic lens.
[0009] Other aspects and advantages of the present invention will
become apparent from the following description, taken in
conjunction with the accompanying drawings, illustrating by way of
example the principles of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The invention, together with objects and advantages thereof,
may best be understood by reference to the following description of
the presently preferred embodiments together with the accompanying
drawings in which:
[0011] FIG. 1(a) is a cross-sectional view showing a prior art
composite lens irradiated with ultraviolet light along a plane
including an optical axis, and
[0012] FIG. 1(b) is a graph showing the amount of ultraviolet light
passing through a plastic lens;
[0013] FIG. 2(a) is a cross-sectional view showing a composite lens
according to a first embodiment of the present invention along a
plane including an optical axis, and
[0014] FIG. 2(b) is a plan view taken from an ultraviolet light
irradiation direction;
[0015] FIG. 3(a) is a cross-sectional diagram showing the composite
lens of the first embodiment irradiated with ultraviolet light
along a plane including the optical axis, and
[0016] FIG. 3(b) is a graph showing the amount of ultraviolet light
passing through a plastic lens;
[0017] FIG. 4(a) is a cross-sectional view showing the composite
lens of the first embodiment along a plane including the optical
axis, and FIG. 4(b) is a graph comparing resin surface shape
difference with the prior art composite lens;
[0018] FIG. 5(a) is a cross-sectional view showing a composite lens
according to a second embodiment of the present invention along a
plane including an optical axis, and
[0019] FIG. 5(b) is a plan view taken from an ultraviolet light
irradiation direction;
[0020] FIG. 6(a) is a cross-sectional view showing a composite lens
according to a third embodiment of the present invention along a
plane including an optical axis, and
[0021] FIG. 6(b) is a plan view taken from an ultraviolet light
irradiation direction;
[0022] FIG. 7 is a partially enlarged view of FIG. 6(a) showing the
composite lens of the third embodiment irradiated with ultraviolet
light; and
[0023] FIG. 8(a) is a cross-sectional view showing a composite lens
according to a fourth embodiment of the present invention along a
plane including an optical axis, and
[0024] FIG. 8(b) is a partially enlarged view of FIG. 8(a).
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0025] In the drawings, like numerals are used for like elements
throughout.
First Embodiment
[0026] A composite lens according to a first embodiment of the
present invention will now be discussed with reference to FIGS. 2
to 4. The composite lens may be used as various types of optical
lenses, such as an image capturing lens. The composite lens is
especially useful when applied as a lens for a compact image
capturing device or an optical reading device.
[0027] Referring to FIG. 2, the composite lens of the first
embodiment includes a plastic lens 1, which serves as a base
material, and an ultraviolet curable resin 2, which is in contact
with one side of an optically effective portion 11 of the plastic
lens 1. The plastic lens is formed by injection molding a
transparent resin. Although not particularly limited, it is
desirable that the transparent resin be ZEONEX E48R manufactured by
Zeon Corporation. The plastic lens 1 is a convex lens, with the
optically effective portion 11 having a center thickness of 0.94 mm
and an optically effective diameter of 1.80 mm. Further, the
plastic lens 1 includes an annular flange 12 having a thickness of
0.35 mm and surrounding the optically effective portion 11. An
annular round groove 13 is formed in the flange 12 around the
optically effective portion 11. The round groove 13 functions as a
diffusion portion for diffusing the irradiated ultraviolet light
toward the resin layer formed by the ultraviolet curable resin 2.
Further, the round groove 13 has a width of 200 .mu.m and a depth
of 50 .mu.m. The flange 12 has a uniform thickness of 0.35 mm
excluding the part where the round groove 13 is formed.
[0028] The ultraviolet curable resin 2, which is in contact with
one side of the plastic lens 1, forms a resin layer functioning as
a concave lens having a center thickness of 0.10 mm. In the
ultraviolet curable resin 2, the part corresponding to the
optically effective portion 11 of the plastic lens 1 has a maximum
thickness of 0.30 mm. The ultraviolet curable resin 2 is not
particularly limited as long as it is transparent and hardened when
irradiated with ultraviolet light. However, it is desirable that
the ultraviolet curable resin 2 be MP202 manufactured by Mitsubishi
Rayon Co., Ltd.
[0029] Referring to FIG. 3(a), a predetermined amount of a gel of
the ultraviolet curable resin 2 is charged into a mold 3. Then, the
mold 3 is closed with the plastic lens 1. This fills the gap
defined by the mold 3 and the plastic lens 1 with the gel of the
ultraviolet curable resin 2 and forms a resin layer. Further, the
ultraviolet curable resin 2 is irradiated with ultraviolet light
and hardened. Afterwards, the mold 3 is removed to complete
production of the composite lens.
[0030] An irradiation path for the ultraviolet light will now be
described in detail with reference to FIGS. 3(a) and 3(b).
[0031] In FIG. 3(b), the horizontal axis (x axis) represents radial
positions on the composite lens, and the vertical axis (y axis)
represents intensity of the ultraviolet light that has passed
through the plastic lens 1. The origin (zero point) of the
horizontal axis (x axis) is located at a point at which the optical
axis of the composite lens intersects with the horizontal axis (x
axis). To facilitate understanding, the horizontal axis (x axis) is
shown in FIG. 3(b) in correspondence with FIG. 3(a).
[0032] As shown in FIG. 3(a), the plastic lens 1 is irradiated with
ultraviolet light 41 from the side opposite the surface that is in
contact with the ultraviolet curable resin 2. The ultraviolet
curable resin 2 is in contact with the mold 3. Thus, the
ultraviolet curable resin 2 is not directly irradiated with the
ultraviolet light 41. The ultraviolet light 41 is formed by light
rays parallel to the optical axis of the plastic lens 1. Thus, the
ultraviolet light 41 irradiates the surface of the plastic lens 1
with a uniform intensity. The plastic lens 1 refracts the
ultraviolet light 41 irradiating the optically effective portion 11
and converges the ultraviolet light 41 in the direction of the
optical axis (i.e., the direction of X=0). Thus, after passing
through the plastic lens 1, the intensity of the ultraviolet light
41, that is, the intensity of the ultraviolet light 41 reaching the
ultraviolet curable resin 2 becomes maximum near the optical axis
of the plastic lens 1 and gradually decreases toward the peripheral
portion. The ultraviolet light 41 irradiating the flange 12 of the
plastic lens 1 at parts excluding the round groove 13 is not
refracted by the plastic lens 1 and thus continues to travel
straight. Therefore, the ultraviolet light 41 that has passed
through the flange 12 has a uniform intensity and is proportional
to the intensity of the ultraviolet light 41 before passing through
the flange 12. Further, the ultraviolet light 41 irradiating the
round groove 13 in the flange 12 of the plastic lens 1 is refracted
and diffused by the plastic lens 1. Some of the diffused light is
directed toward the optically effective portion 11. This increases
the ultraviolet light intensity near the periphery of the optically
effective portion 11 in the composite lens of the first embodiment,
which is shown by the solid lines in FIG. 3(b), compared with the
ultraviolet light intensity in the prior art, which is shown by the
broken lines in FIG. 3(a). Further, the region in which the
ultraviolet light intensity is minimum is moved in the peripheral
direction from the position where the intensity is minimum in the
prior art (i.e., the position corresponding to X=.+-.0.8). This
prevents insufficient hardening of the ultraviolet curable resin 2
near the periphery of the part contacting the optically effective
portion 11.
[0033] The effect of the round groove 13 in the first embodiment
will now be discussed with reference to FIGS. 4(a) and 4(b).
[0034] FIG. 4(b) is a diagram comparing variations in the thickness
of the resin layer between the first embodiment and the prior art.
In FIG. 4(b), the horizontal axis (x axis) represents radial
positions on the composite lens, and the vertical axis (y axis)
represents the difference between the actually measured thickness
and the designed thickness of the resin layer (hereafter, referred
to as the "resin surface shape difference"). The origin (zero
point) of the horizontal axis (x axis) is located at a point at
which the optical axis of the composite lens intersects with the
horizontal axis (x axis). To facilitate understanding, the
horizontal axis (x axis) is shown in FIG. 4(b) in correspondence
with FIG. 4(a). To measure the resin layer thickness, NH-3SP, which
is a non-contact three-dimensional measurement device manufactured
by Mitaka Kohki Co., Ltd. was used, and the thickness was measured
for a range extending 0.9 mm from the center point in opposite
directions (optically effective radius range).
[0035] As is apparent from FIG. 4(b), in comparison with the resin
surface shape difference of the prior art shown by the broken line,
the resin surface shape difference of the first embodiment shown by
the solid line is smaller especially near the periphery of the
optically effective portion 11 (i.e., positions outward from the
position corresponding to x=.+-.0.75). This shows that in the
composite lens of the prior art, insufficient hardening of the
ultraviolet curable resin near the periphery of the optically
effective portion resulted in insufficient accuracy subsequent to
hardening. In other words, the first embodiment prevents
insufficient hardening and increases accuracy subsequent to
hardening.
[0036] The composite lens of the first embodiment has the
advantages described below.
[0037] (1) The round groove 13 in the flange 12 diffuses the
irradiated ultraviolet light. This increases the intensity of the
ultraviolet light that irradiates the ultraviolet curable resin 2,
which is in contact with the optically effective portion 11.
Accordingly, the ultraviolet light intensity near the periphery of
the optically effective portion 11 is prevented from decreasing. As
a result, insufficient hardening at this part of the ultraviolet
curable resin 2 is prevented.
[0038] Further, as shown in FIGS. 4(a) and 4(b), the resin surface
shape difference at the part near the periphery of the optically
effective portion of the composite lens is improved. Thus, the
thickness of the ultraviolet curable resin 2 is close to the
designed value.
[0039] (2) The round groove 13 is annular and surrounds the
optically effective portion 11. Thus, the ultraviolet light
diffused by the round groove 13 reaches parts near the entire
periphery of the optically effective portion 11.
[0040] (3) The advantages described above are obtained just by
forming the round groove 13 in the flange 12. The round groove 13
can be formed at the same time as when injection molding the
plastic lens 1. This simplifies production of the composite lens
and lowers costs.
Second Embodiment
[0041] A composite lens according to a second embodiment of the
present invention will now be discussed with reference to FIGS.
5(a) and 5(b). The second embodiment differs from the first
embodiment only in the structure of the flange 12. Parts that are
the same as the first embodiment will not be described.
[0042] As shown in FIGS. 5(a) and 5(b), the flange 12 of the second
embodiment includes an annular embossed surface 14, which includes
pits and lands and which surrounds the optically effective portion
11. The embossed surface 14 functions as a diffusion portion for
diffusing the irradiated ultraviolet light toward the resin layer.
The embossed surface 14 has a width of 200 .mu.m and a centerline
average roughness Ra of 0.5 .mu.m or greater. To diffuse
ultraviolet light, it is desirable that the roughness Ra be greater
than the median wavelength of the ultraviolet light (365 nm). The
embossed surface 14 may be formed when injection molding the
plastic lens 1 or by using a chemical agent after the injection
molding to cause erosion in the surface of the plastic lens 1.
[0043] The second embodiment has the advantages described
below.
[0044] (1) The embossed surface 14 in the flange 12 diffuses the
irradiated ultraviolet light. As a result, some of the diffused
ultraviolet light reaches the ultraviolet curable resin 2
contacting the optically effective portion 11. This increases the
intensity of the ultraviolet light irradiating the ultraviolet
curable resin 2 that is in contact with the optically effective
portion 11 in comparison with the prior art. Accordingly, the
intensity of the ultraviolet light near the periphery of the
optically effective portion 11 is prevented from decreasing. Thus,
insufficient hardening of the ultraviolet curable resin 2 at this
part is prevented. As a result, although not particularly shown in
the drawings, the resin surface shape difference is improved near
the periphery of the optically effective portion 11 in the
composite lens. Therefore, it can be assumed that the thickness of
the ultraviolet curable resin 2 is close to the designed value.
[0045] (2) The embossed surface 14 is annular and surrounds the
optically effective portion 11. Thus, the ultraviolet light
diffused by the embossed surface 14 reaches parts near the entire
periphery of the optically effective portion 11.
[0046] (3) The advantages described above are obtained just by
forming the embossed surface 14 in the flange 12. The embossed
surface 14 can be formed at the same time as when injection molding
the plastic lens 1. Alternatively, the embossed surface 14 may be
formed by using a chemical agent after the injection molding to
cause erosion in the surface of the plastic lens 1. This simplifies
production of the composite lens and lowers costs.
Third Embodiment
[0047] A composite lens according to a third embodiment of the
present invention will now be discussed with reference to FIGS.
6(a), 6(b), and 7. The third embodiment differs from the first
embodiment in the structure of the flange 12. Parts that are the
same as the first embodiment will not be described.
[0048] As shown in FIG. 6(a) and 6(b), the flange 12 of the third
embodiment includes an annular round projection 15, which surrounds
the optically effective portion 11. The round projection 15 has a
width of 100 .mu.m and projects from the flange 12 to a height of
50 .mu.m. As shown in FIG. 7, the round projection 15 first
converges ultraviolet light and then diffuses the converged light
so that the diffused light reaches the ultraviolet curable resin 2
contacting the optically effective portion 11. That is, the round
projection 15 functions as a diffusion portion for diffusing the
irradiated ultraviolet light toward the resin layer. Thus, the
round projection 15 must have a large refractive index. The round
projection 15 is formed by a mold when injection molding the
plastic lens 1. When forming the round projection 15 with a mold,
to sustain the strength of the mold, it is desirable that the round
projection 15 be spaced outward by 50 .mu.m or farther from the
periphery of the optically effective portion 11.
[0049] The composite lens of the third embodiment has the
advantages described below.
[0050] (1) The round projection 15 on the flange 12 first converges
and then diffuses the irradiated ultraviolet light. As a result,
some of the diffused ultraviolet light reaches the ultraviolet
curable resin 2 contacting the optically effective portion 11. This
increases the intensity of the ultraviolet light irradiating the
ultraviolet curable resin 2 that is in contact with the optically
effective portion 11 in comparison with the prior art. Accordingly,
the intensity of the ultraviolet light near the periphery of the
optically effective portion 11 is prevented from decreasing. Thus,
insufficient hardening of the ultraviolet curable resin 2 at this
part is prevented. As a result, although not particularly shown in
the drawings, the resin surface shape difference is improved near
the periphery of the optically effective portion 11 in the
composite lens. Therefore, it can be assumed that the thickness of
the ultraviolet curable resin 2 is close to the designed value.
[0051] (2) The round projection 15 is annular and surrounds the
optically effective portion 11. Thus, the ultraviolet light
diffused by the round projection 15 reaches parts near the entire
periphery of the optically effective portion 11.
[0052] (3) The advantages described above are obtained just by
forming the round projection 15 on the flange 12. The round
projection 15 can be formed at the same time as when injection
molding the plastic lens 1. This simplifies production of the
composite lens and lowers costs.
Fourth Embodiment
[0053] A composite lens according to a fourth embodiment of the
present invention will now be discussed with reference to FIGS.
8(a) and 8(b). The fourth embodiment differs from the first
embodiment in the structure of the flange 12. Parts that are the
same as the first embodiment will not be described.
[0054] As shown in FIGS. 8(a) and 8(b), the flange 12 of the fourth
embodiment 12 includes an annular diffraction grating 16, which
surrounds the optically effective portion 11. The diffraction
grating 16 functions as a diffusion portion for diffusing the
irradiated ultraviolet light toward the resin layer. The
diffraction grating 16 has a width of 200 .mu.m and a grating
spacing (pitch) of 1.33 .mu.m. To direct ultraviolet light toward a
region of the ultraviolet curable resin 2 where hardening is
insufficient, the diffraction grating 16 must refract ultraviolet
light within a range of refractive angle
.theta.=8.degree..about.15.degree.. Accordingly, the diffraction
grating 16 is formed based on the relationship of the equation
shown below.
nsin.theta.=.lamda./P (1)
[0055] In the equation, n represents the refractive index, .theta.
represents the refractive angle, .lamda. represents the wavelength,
and P represents the diffraction grating pitch. In a state
represented by n=1, .lamda.=365 nm, and
.theta.=8.degree..about.15.degree., it is required that
P=1.0.about.1.7 .mu.m be satisfied. In the fourth embodiment, the
pitch P of the diffraction grating 16 is 1.33 .mu.m and thus
satisfies the above requirement. The diffraction grating 16 is
formed by a mold when injection molding the plastic lens 1.
[0056] The composite lens of the fourth embodiment has the
advantages described below.
[0057] (1) The diffraction grating 16 of the flange 12 refracts the
irradiated ultraviolet light. As a result, some of the diffused
ultraviolet light reaches the ultraviolet curable resin 2
contacting the optically effective portion 11. This increases the
intensity of the ultraviolet light irradiating the ultraviolet
curable resin 2 that is in contact with the optically effective
portion 11 in comparison with the prior art. Accordingly, the
intensity of the ultraviolet light near the periphery of the
optically effective portion 11 is prevented from decreasing. Thus,
insufficient hardening of the ultraviolet curable resin 2 at this
part is prevented. As a result, although not particularly shown in
the drawings, the resin surface shape difference is improved near
the periphery of the optically effective portion 11 in the
composite lens. Therefore, it can be assumed that the thickness of
the ultraviolet curable resin 2 is close to the designed value.
[0058] (2) The diffraction grating 16 is annular and surrounds the
optically effective portion 11. Thus, the ultraviolet light
diffused by the diffraction grating 16 reaches parts near the
entire periphery of the optically effective portion 11.
[0059] (3) The advantages described above are obtained just by
forming the diffraction grating 16 on the flange 12. The
diffraction grating 16 can be formed at the same time as when
injection molding the plastic lens 1. This simplifies production of
the composite lens and lowers costs.
[0060] It should be apparent to those skilled in the art that the
present invention may be embodied in many other specific forms
without departing from the spirit or scope of the invention.
Particularly, it should be understood that the present invention
may be embodied in the following forms.
[0061] In the first to fourth embodiments, the diffusion portion
continuously surrounds the entire optically effective portion 11.
However, as long as the ultraviolet curable resin 2 can be
sufficiently hardened, the diffusion portion may be formed in a
non-continuous manner on the flange 12. This would simplify
production of the composite lens and increase the strength of the
lens.
[0062] The diffusion portion for diffusing the ultraviolet light is
not limited to the round groove 13, the embossed surface 14, the
round projection 15, or the diffraction grating 16 as in the first
to fourth embodiments.
[0063] The present examples and embodiments are to be considered as
illustrative and not restrictive, and the invention is not to be
limited to the details given herein, but may be modified within the
scope and equivalence of the appended claims.
* * * * *